The present invention relates to antifriction bearings having a lubricant supply system wherein one of the bearing rings is provided with a lubricant supply duct. Antifriction bearings of this type are known from "Konstruktion von Spindel-Lager-Systemen fur die Hochgeschwindigceits-Materialbearbeitung," Manfred Weck et al., expert Verlag, Ehningen.
In these antifriction bearings, a cleaning of the antifriction bearing by flushing occurs along with the lubricant supply. As a result, there is always more lubricant supplied into the antifriction bearing than needed. It is therefore necessary to remove and discharge the excessive lubricant. Also, additional work energy must be applied to compensate for "splash" work loss, and also an additional heating of the bearing occurs as a consequence of the splash work, as well as a wear of lubricant. EP 350 734 also discloses devices for supplying a lubricant to antifriction bearings. In these antifriction bearings, the lubricant is supplied through conduits, or nozzles, through which the lubricant mixed with an air current is blown into the bearing.
A disadvantage of this embodiment is that besides the supply of lubricant to the point of lubrication, the environment is contaminated by the lubricant. Moreover, this type of construction causes a relatively high lubricant consumption, since besides the lubricant required for the actual point of lubrication, it is also necessary to consider the loss of lubricant which is blown into the environment.
While the selection of a relatively highly viscous lubricant allows these losses to be relatively low, they cannot be entirely avoided. On the other hand, highly viscous lubricants for certain applications, interfere with the easy motion of a bearing, as is required in particular for godets for yarns, which rotate at a very high speed and substantially free of resistance. In particular in the case of godets, the contamination of the environment by oil mist is of relevant importance, since it is absolutely necessary to prevent the product from being soiled.
It is also known to provide such antifriction bearings with a permanent filling or lubrication, the bearing in this instance being hermetically sealed by means of washers arranged on both sides of the rolling element.
Prerequisite for such a permanent lubrication are correspondingly pasty, or highly viscous lubricants, so as to ensure a long-term sealing of the antifriction bearing. However, this in turn has the disadvantage that the viscosity of the lubricant is highly dependent on the temperature of is the bearing.
It is therefore the object of the present invention to further develop the supply of lubricant to antifriction bearings, so as to ensure with a low lubricant throughput an effective and substantially lossfree lubrication of the antifriction bearing.